U.S. patent application number 12/160428 was filed with the patent office on 2010-06-24 for hydraulic machine, in particular hydraulic motor, and metering device comprising such a motor.
This patent application is currently assigned to DOSATRON INTERNATIONAL. Invention is credited to Gilbert Barras, Dominique Berton, Matthieu Darbois, Gregory Lucas.
Application Number | 20100154625 12/160428 |
Document ID | / |
Family ID | 36499278 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100154625 |
Kind Code |
A1 |
Darbois; Matthieu ; et
al. |
June 24, 2010 |
HYDRAULIC MACHINE, IN PARTICULAR HYDRAULIC MOTOR, AND METERING
DEVICE COMPRISING SUCH A MOTOR
Abstract
A hydraulic machine includes a casing with a body and a cover; a
separation member which can make a reciprocating movement and
defines two chambers; hydraulic switching elements including a
distribution member; a compartment in the body of the casing
connected to a pressurized-liquid inlet, and initiating elements
including a pusher connected to the separation member, these
initiating elements being able, at the end of the stroke, to cause
a sudden change in the position of the switching elements, under
the action of an elastic member to reverse the stroke. The
distribution member has a distribution slide valve applied against
a flat plate which is fixed relative to the body of the casing, the
slide valve being able to slide in a fluid-type manner, without a
seal, against the plate, which has orifices connected respectively
to the chambers and to a liquid outlet orifice.
Inventors: |
Darbois; Matthieu;
(Bordeaux, FR) ; Lucas; Gregory; (Saint Loubes,
FR) ; Barras; Gilbert; (Carignan De Bordeaux, FR)
; Berton; Dominique; (Le Bouscat, FR) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
DOSATRON INTERNATIONAL
Tresses
FR
|
Family ID: |
36499278 |
Appl. No.: |
12/160428 |
Filed: |
December 7, 2006 |
PCT Filed: |
December 7, 2006 |
PCT NO: |
PCT/FR2006/002674 |
371 Date: |
July 10, 2008 |
Current U.S.
Class: |
91/346 |
Current CPC
Class: |
F04B 9/107 20130101 |
Class at
Publication: |
91/346 |
International
Class: |
F15B 13/04 20060101
F15B013/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 13, 2006 |
FR |
06/00314 |
Claims
1. A hydraulic machine, in particular a hydraulic motor,
comprising: a casing (2) comprising a body (3) and a cover (4); a
separation means (M) suitable for making an alternating movement in
the casing between the body and cover, this separation means
defining two chambers (5, 6); hydraulic switching means (C) for the
supply with liquid and the emptying of the chambers, these
switching means comprising a distribution member (D) that is able
to take two stable positions and is controlled by the movements of
the separation means; a compartment (13) in the body of the casing
connected to a pressurized liquid inlet and in which the switching
means (C) are housed, and triggering means (15), comprising a
pushbutton (A) connected to the separation means, suitable for
initiating, at the end of travel, a sudden change of the position
of the switching means, under the action of an elastic means (E),
for the inversion of travel, characterized in that the distribution
member (D) comprises a distribution slide valve (16) pressed
against a flat plate (17) that is fixed relative to the body of the
casing, the distribution slide valve (16) being able to slide
sealingly, without a seal, against the plate (17) which comprises
orifices connected respectively to the chambers (5, 6) of the
casing and to an orifice (18) for the outlet of the liquid, the
distribution slide valve (16) being provided in order, depending on
its position, to close certain of the orifices or place them in
communication with the fluid inlet or the exhaust.
2. The machine as claimed in claim 1, characterized in that the
elastic means (E) consists of a spring (36) in the shape of an arc
of a curve of which one end (36a) is connected to a link rod (37)
articulated on a shaft (38) supported by the body (3) of the
casing, one end (40) of the link rod being connected to the
pushbutton (A), while the other end (36b) of the spring is
connected in translation to the slide valve (36), this other end
(36b) moving from one stable position to another stable position by
deformation of the spring (36).
3. The machine as claimed in claim 2, characterized in that the
link rod (37) is fixedly attached to at least one arm (45) pressing
against a stop (46) of the slide valve (16) at the time of the
inversion of the direction of movement in order to assist the force
of the spring at the beginning of the movement of the slide
valve.
4. The machine as claimed in claim 2, characterized in that the end
(36a) of the spring in the shape of an arc of a curve connected to
the pushbutton (A) travels, during the movement of the pushbutton
(A), from one side to the other of the shaft (38) of articulation
of the link rod.
5. The machine as claimed in claim 2, characterized in that the end
(36b) of the spring in the shape of an arc of a curve connected to
the slide valve (16) is received in a housing (43) lying in the
direction of movement of the slide valve.
6. The machine as claimed in claim 2, characterized in that the
spring (36) is made of plastic, and articulation pins provided at
each end (36a, 36b) are molded in a single piece with this
spring.
7. The machine as claimed in claim 1, characterized in that the
flat plate (17) comprises five orifices spaced out in the direction
of sliding of the slide valve (17), namely a central orifice (5)
connected to the outlet (18) of the hydraulic machine and, on
either side of the central orifice, two spaced out orifices (E5,
P5; E6, P6) connected to a chamber (5, 6) of the machine, the slide
valve (16) comprising at its longitudinal ends a means (32, 33) for
shutting off an orifice of the plate and, between its ends, a space
(34) for communication between at least two orifices of the
plate.
8. The machine as claimed in claim 7, characterized in that the
spacing between the central orifice (S) and an adjacent orifice
(E5, E6) of the plate is less than the spacing between this
adjacent orifice (E5, E6) and the end orifice (P5, P6) situated on
the same side, the communication space (34) of the slide valve
ensuring, during the inversion of the direction of movement of the
separation means (M), that the two chambers (5, 6) are placed in
communication with the outlet (18) and hence that the inlet (14) is
placed in communication with the outlet (18).
9. The machine as claimed in claim 7, characterized in that each
means for shutting off the slide valve (16) consists of a shutoff
zone (32, 33) delimited by two walls transverse to the direction of
movement, suitable for closing an orifice of the plate when it is
in line with this orifice, and the communication space (34) of the
slide valve, comprised between the shutoff zones, is limited by a
wall (35) at a distance from the plate.
10. The machine as claimed in claim 1, characterized in that the
slide valve (16) and the flat plate (17) are placed parallel to the
direction of movement of the pushbutton (A).
11. The machine as claimed in claim 1, characterized in that the
surface of the flat plate (17) in contact with the slide valve (16)
is a glass sheet.
12. The machine as claimed in claim 1, characterized in that the
flat plate (17) is made of ceramic.
13. The machine as claimed in claim 1, characterized in that the
distribution slide valve (16) is made of plastic.
14. The machine as claimed in claim 1, characterized in that the
separation means is a membrane (7).
15. A proportional metering device for liquid, characterized in
that it comprises a hydraulic motor as claimed in claim 1, and an
additive-metering subassembly (21) actuated by the motor.
16. The metering device as claimed in claim 15, characterized in
that it comprises a separation plug (25) provided in the bottom of
the compartment (13) containing the switching means (C), this plug
(25) being traversed by a piston (24) of the metering subassembly
(21) connected to the pushbutton (A) and a pipe (26) emerging
beneath the plug (25) and connected to the outlet (18).
17. The machine as claimed in claim 3, characterized in that the
end (36a) of the spring in the shape of an arc of a curve connected
to the pushbutton (A) travels, during the movement of the
pushbutton (A), from one side to the other of the shaft (38) of
articulation of the link rod.
18. The machine as claimed in claim 3, characterized in that the
end (36b) of the spring in the shape of an arc of a curve connected
to the slide valve (16) is received in a housing (43) lying in the
direction of movement of the slide valve.
19. The machine as claimed in claim 3, characterized in that the
spring (36) is made of plastic, and articulation pins provided at
each end (36a, 36b) are molded in a single piece with this
spring.
20. The machine as claimed in claim 8, characterized in that each
means for shutting off the slide valve (16) consists of a shutoff
zone (32, 33) delimited by two walls transverse to the direction of
movement, suitable for closing an orifice of the plate when it is
in line with this orifice, and the communication space (34) of the
slide valve, comprised between the shutoff zones, is limited by a
wall (35) at a distance from the plate.
Description
[0001] The invention relates to a hydraulic machine, in particular
a hydraulic motor, of a type like those that comprise: [0002] a
casing comprising a body and a cover; [0003] a separation means
suitable for making an alternating movement in the casing between
the body and cover, this separation means defining two chambers;
[0004] hydraulic switching means for the supply with liquid and the
emptying of the chambers, these switching means comprising a
distribution member that is able to take two stable positions and
is controlled by the movements of the separation means; [0005] a
compartment in the body of the casing connected to a pressurized
liquid inlet and in which the switching means are housed, [0006]
and triggering means, comprising a pushbutton connected to the
separation means, suitable for initiating, at the end of travel, a
sudden change of the position of the switching means, under the
action of an elastic means, for the inversion of travel.
[0007] The hydraulic machines of this kind, particularly the
hydraulic motors for proportional metering devices, operate for the
most part with a distribution system of the "valve box" type. The
valve box is a fluid distribution system consisting of an inlet and
exhaust valve through a working chamber, the valves being furnished
with seals.
[0008] Such a type of distribution imposes an architecture and a
geometry on the hydraulic machine, and on the proportional metering
device incorporating such a hydraulic machine, creating problems
for maintenance. Specifically, the installation and removal of such
a valve box is often difficult because of a narrow access and often
makes it necessary to remove other elements of the metering device.
In addition, it is practically inevitable to have to replace the
valve seals during the lifetime of the metering device.
[0009] The principal object of the invention is to provide a
hydraulic machine, particularly a hydraulic motor, whose switching
means make it possible to clearly separate the distribution
mechanism from the drive portion, so that these elements can be
removed independently of one another.
[0010] A further object of the invention is to reduce the number of
parts comprising the machine, in particular at the switching means,
and to reduce the maintenance operations.
[0011] According to the invention, a hydraulic machine,
particularly a hydraulic motor, of the kind defined above is
characterized in that the distribution member comprises a
distribution slide valve pressed against a flat plate that is fixed
relative to the body of the casing, the distribution slide valve
being able to slide sealingly, without a seal, against the plate
which comprises orifices connected respectively to the chambers of
the casing and to an orifice for the outlet of the liquid, the
distribution slide valve being provided in order, depending on its
position, to close certain of the orifices or place them in
communication with the fluid inlet or the exhaust.
[0012] The elastic means consists advantageously of a spring in the
shape of an arc of a curve of which one end is connected to a link
rod articulated on a shaft supported by the body of the casing, one
end of the link rod being connected to the pushbutton, while the
other end of the spring is connected in translation to the slide
valve, this other end moving from one stable position to another
stable position by deformation of the spring.
[0013] Preferably, the link rod is fixedly attached to at least one
arm pressing against a stop of the slide valve at the time of the
inversion of the direction of movement in order to assist the force
of the spring at the beginning of the movement of the slide
valve.
[0014] The end of the spring in the shape of an arc of a curve
connected to the pushbutton travels, during the movement of the
pushbutton, from one side to the other of the shaft of articulation
of the link rod. The end of the spring in the shape of an arc of a
curve connected to the slide valve is received in a housing lying
in the direction of movement of the slide valve.
[0015] The spring is advantageously made of plastic, and
articulation pins provided at each end are molded in a single piece
with this spring.
[0016] The flat plate preferably comprises five orifices spaced out
in the direction of sliding of the slide valve, namely a central
orifice connected to the outlet of the hydraulic machine and, on
either side of the central orifice, two spaced out orifices
connected to a chamber of the machine, the slide valve comprising
at its longitudinal ends a means for shutting off an orifice of the
plate and, between its ends, a space for communication between at
least two orifices of the plate. Preferably, the spacing between
the central orifice and an adjacent orifice of the plate is less
than the spacing between this adjacent orifice and the end orifice
situated on the same side, the communication space of the slide
valve ensuring, during the inversion of the direction of movement
of the separation means, that the two chambers are placed in
communication with the outlet and hence that the inlet is placed in
communication with the outlet.
[0017] Each means for shutting off the distribution slide valve
comprises a shutoff zone delimited by two walls transverse to the
direction of movement, suitable for closing an orifice of the plate
when it is in line with this orifice, and the communication space
of the distribution slide valve, comprised between the shutoff
zones, is limited by a wall at a distance from the plate.
[0018] The distribution slide valve and the flat plate are placed
parallel to the direction of movement of the pushbutton.
Preferably, the surface of the flat plate in contact with the slide
valve is a glass sheet. The flat plate may be made of ceramic. The
slide valve may be made of plastic.
[0019] The separation means is advantageously a membrane.
[0020] The invention also relates to a proportional metering device
for an additive in a main liquid, characterized in that it
comprises a hydraulic motor as defined above, and an
additive-metering subassembly actuated by the motor.
[0021] The metering device may comprise a separation plug provided
in the bottom of the compartment containing the switching means,
this plug being traversed by a piston of the metering subassembly
connected to the pushbutton and a pipe emerging beneath the plug
and connected to the outlet.
[0022] Apart from the arrangements explained above, the invention
consists of a certain number of other arrangements that will be
more explicitly explained below with reference to an exemplary
embodiment that is described with reference to the appended
drawings but that is in no way limiting. In these drawings:
[0023] FIG. 1 is a schematic vertical section of a proportional
metering device with a hydraulic motor according to the
invention.
[0024] FIG. 2 is an exploded view in perspective of the main parts
of the metering device and of the hydraulic motor.
[0025] FIG. 3 is a diagram illustrating a first extreme position of
the glass sheet and of the slide valve turned over on the side in
order to make the explanations easier.
[0026] FIG. 4 shows, like FIG. 3, the glass sheet and the slide
valve in an intermediate position.
[0027] FIG. 5 shows, like FIG. 3, the glass sheet and the slide
valve in another extreme position, opposite to that of FIG. 3.
[0028] FIG. 6 is a schematic vertical section of the glass sheet
and of the slide valve shown horizontally, in an extreme
position.
[0029] FIG. 7 is a view in elevation of the slide valve and the
link rod of FIG. 6.
[0030] FIG. 8 shows, like FIG. 6, the link rod switched over.
[0031] FIG. 9 is a view in elevation of the link rod and the slide
valve of FIG. 8.
[0032] FIG. 10 is a schematic section similar to FIG. 8 of the link
rod and the slide valve during sliding.
[0033] FIG. 11 shows in elevation the slide valve and the link rod
in the position of FIG. 10.
[0034] FIG. 12 is a schematic section similar to FIG. 10 of the
link rod and the slide valve in another extreme position for
controlling the inversion and the change of direction of the liquid
flows,
[0035] and FIG. 13 shows in elevation the slide valve and the link
rod in the position of FIG. 12.
[0036] With reference to the drawings, in particular FIGS. 1 and 2,
it is possible to see a proportional metering device comprising a
hydraulic motor 1, for a metered injection of additive into a main
liquid that actuates the motor. The motor 1 comprises a casing 2
formed of a body 3 and a cover 4. The body and the cover are
assembled in a removable manner, by bolts and nuts not shown,
passing through holes provided in twinned flanges. The cover 4 is
fitted with a bleed Am to exhaust the air from the metering
device.
[0037] A separation means M suitable for carrying out an
alternating movement, in a volume comprised between the body 3 and
the cover 2, defines two chambers 5 and 6. The separation means M
advantageously consists of a deformable membrane 7 whose periphery
comprises a rim gripped in a sealed manner between the cover 4 and
the body 3. This exemplary embodiment of the separation means M is
not limiting, the invention being able to apply to a machine whose
separation means consists of a piston.
[0038] The chamber 5, situated above the membrane 7 when the motor
is placed with its vertical axis as illustrated in FIG. 1, is
limited by an internal concave surface 8 of the cover 4. The
central portion of the membrane 7 comprises a circular opening
whose edge is gripped in a sealed manner between a disk 9 housed
essentially in the chamber 6 and a ring 10 housed in the chamber 5.
The ring 10 may, at the top end of travel of the membrane 7, press
against a rib 11 of the internal surface 8.
[0039] The chamber 6 is delimited, on the side opposite to the
membrane 7, by a cylindrical cavity whose bottom 12 comprises a
passageway for a pushbutton A.
[0040] Hydraulic switching means C are provided in order to supply
with liquid and empty the chambers 5 and 6. These switching means C
comprise a distribution member D that is able to take two stable
positions and are controlled by the movements of the membrane
7.
[0041] The switching means C are housed in a compartment 13 of the
body 3 of the casing, connected to a pressurized liquid inlet
14.
[0042] Triggering means 15, comprising the pushbutton A connected
to the membrane 7, are suitable for causing at the top and bottom
ends of travel a sudden change of the position of the switching
means C under the action of an elastic means B, for the inversion
of the travel of the membrane 7.
[0043] The distribution member D comprises a distribution slide
valve 16 pressed against a flat plate 17 that is fixed relative to
the body 3 of the casing.
[0044] The plate 17 consists of a glass sheet, that is to say that
the surface of the plate 17 in contact with the distribution slide
valve 16 has a high degree of flatness corresponding to a mirror
polish. The twinned surface of the slide valve 16 also has a high
degree of flatness, such that a leaktightness of contact with no
seal is established between the glass sheet 17 and the slide valve
16. The plate 17 is advantageously made of ceramic while the slide
valve 16 is made of plastic.
[0045] For the liquid to pass through, the plate 17 comprises five
orifices spaced out in the direction of sliding of the slide valve
16, the vertical direction according to the example of FIG. 1.
[0046] The plate 17 and the slide valve 16 are placed parallel to
the direction of movement of the pushbutton A and at right angles
to the geometric axis of the inlet 14. The slide valve 16 may slide
against the plate 17 parallel to the direction of movement of the
pushbutton A.
[0047] The plate 17 comprises a central orifice S connected to the
outlet 18 of the hydraulic machine and, on either side of the
central orifice in the direction of movement of the slide valve,
two spaced out orifices E5, P5 and E6, P6 connected via pipes
provided in a part 19 attached against the body 3 of the machine.
The part 19 is itself connected by two elbows 20 (FIG. 2) to the
upper chamber 5. The connections with the lower chamber 6 are shown
only partially.
[0048] The lower portion of the compartment 13 is open and receives
a metering subassembly 21 with a suction valve furnished with an
end-piece 23 to which a duct can be connected immersed in a
receptacle (not shown) of additive sucked in a metered quantity.
The metering subassembly 21 comprises a suction piston 24 coupled
to the pushbutton A.
[0049] According to the example shown in FIG. 1, the piston 24
passes through a separation plug 25 provided in the bottom of the
compartment 13. The additive liquid pumped by the piston 24 is
discharged toward the outlet 18 through a pipe 26 which emerges
beneath the plug 25. The mixing of the additive, pumped by the
subassembly 21, with the main liquid arriving via the inlet 14
takes place at the outlet 18.
[0050] As a variant, the mixing of the additive and the main liquid
could take place in the compartment 13 by removing the plug 25 and
closing the pipe 26.
[0051] As can be seen in FIG. 6, the plate 17 is housed in a recess
27 provided in a block 28 made of plastic comprising holes 29 for
attachment to the part 19, and end-of-travel stops 30, 31 for the
slide valve 16.
[0052] The spacing between the central orifice S and the plate 17
and an adjacent orifice E5 or E6 is less than the spacing between
this orifice E5 or E6 and the end orifice P5 or P6 situated on the
same side. The pitch between the orifices is therefore shifted,
which has a value that is explained below.
[0053] The slide valve 16 comprises, at each of its longitudinal
ends, a shutoff means comprising a zone 32, 33 for shutting off an
orifice of the plate 17 and, between the shutoff zones, a space 34
for communication between at least two orifices of the plate
17.
[0054] Each shutoff zone 32, 33 of the slide valve 16 is delimited
by two walls transverse to the direction of movement, ensuring a
virtually linear contact with the plate 17, favorable to the
establishment of a good seal. Between the transverse walls of
pressure against the plate 17, the wall of the shutoff zones 32, 33
is parallel to the plate 17 and at a distance from its surface. The
communication space 34 situated between the shutoff zones 32, 33 is
limited by a dome-shaped wall 35.
[0055] The elastic means B consists of a leaf spring 36 in the
shape of an arc of a curve whose convexity is turned toward the
upper portion of the body 3. One end 36a of the spring is connected
to the pushbutton A while the other end 36b is connected in
translation to the slide valve 16. Each end 36a, 36b is
advantageously formed by a cylindrical pin whose generatrices are
orthogonal to the mid-plane of the leaf spring 36, and to the
direction of movement of the pushbutton A, these cylindrical pins
forming articulation shafts. The spring 36 is preferably made of
plastic in a single piece with the pins 36a, 36b. The pins of the
ends 36a, 36b protrude transversely on either side of the leaf
spring 36 along its width.
[0056] The lateral protrusions of the end 36a, as can be seen in
FIG. 2, are received in respective housings provided at one end of
two parallel branches of a link rod 37, these branches framing the
spring 36. Each housing receiving the end 36a is open so that the
end 36a can be easily engaged in and disengaged from the housings
of the link rod 37 by simply deforming the spring 36.
[0057] The link rod 37 is articulated, at its end distant from 36a,
on a shaft 38 supported, at each of its ends, by an element 39
(FIG. 2) substantially in the shape of an isosceles triangle, with
an internal opening, whose base is fixedly attached to the part 19
and the body 3, and whose top zone comprises a bearing for the end
of the shaft 38. The two supports 39 frame the slide valve 16 and
the link rod 37.
[0058] The end of each branch of the link rod 37 opposite to the
shaft 38 and to which the end 36a of the spring 36 is attached
comprises a cheek 40 in which a housing for the end 36a is
provided. Each cheek 40 has a substantially circular shape and is
housed, with the ability to rotate, in a horizontal groove 41. Each
groove 41 is provided in a vertical inner wall of a rectangular
window 42 arranged in the portion of the pushbutton A that is in
the compartment 13. Each groove 41 opens, on the side of the plate
17, through a flared portion allowing an inclination of the link
rod as illustrated in FIG. 1.
[0059] When the cheeks 40 are operated in translation by the
pushbutton A, this arrangement allows the link rod 37 to rotate
about the shaft 38.
[0060] The other end 36b of the spring 36 is received in a
rectangular housing 43, lying in the direction of movement of the
slide valve 16. Such a housing 43 is provided in each of the two
side walls 44 of the slide valve 16, which frame the spring 36. The
housing 43 is open in the direction opposite to the plate 17 and
the force of the spring 36 presses the end 36b against the bottom
of the housing 43. The installation of the pin forming the end 36b
into the housing 43 is simple and quick, as is the removal.
[0061] The end 36b may occupy a stable position illustrated in FIG.
1 and FIG. 12 in which it is butting against the transverse wall of
the housing 43 furthest from the chamber 6. The slide valve 16 then
occupies the bottom position illustrated in FIG. 1. In another
stable position represented in FIG. 6, the end 36b of the spring is
pressing against the transverse wall of the housing 43 closest to
the chamber 6, and the slide valve 16 occupies the top position
opposite to that of FIG. 1.
[0062] The end 36a of the spring connected to the pushbutton A by
the link rod 37 travels, during the vertical movement of the
pushbutton, from one side to the other of the articulation shaft 38
of the link rod 37. This travel triggers the switching and the
change of position of the slide valve.
[0063] The link rod 37 is fixedly attached to at least one arm
substantially orthogonal to the link rod and extending on either
side of this link rod as can be seen in FIGS. 6 to 13. The arm 45
has the shape of a walking beam whose ends 45a, 45b are bent and
rounded in order to come into contact, at the moment of inversion
of the movement of the membrane, with a stop 46, for example in the
shape of a prism, provided to protrude on the outer face of the
side wall 44 of the slide valve, mid-way along, beneath the
rectangular housing 43.
[0064] Preferably, two parallel arms 45 are provided and frame the
slide valve 16, in order to press simultaneously against the stops
46.
[0065] The switching phases obtained with the slide valve 16 and
the plate 17 are illustrated in FIGS. 3, 4 and 5. To make the
drawings easier to understand, the slide valve 16 has been shown
turned over whereas, in reality, it slides against the plate 17 in
a position orthogonal to that shown in these figures. The width of
the slide valve 16 is greater than that of the orifices of the
plate 17 so that, when an orifice is covered by one of the end
shutoff zones 32 or 33 of the slide valve, this orifice is
completely closed.
[0066] FIG. 3 represents a first extreme stable position of the
slide valve 16 in which the shutoff zone 32 closes the orifice E5
connected to the chamber 5, while the shutoff zone 33 closes the
orifice P6 connected to the chamber 6. The intermediate space 34
places the orifice E6, and hence the chamber 6, in communication
with the fluid outlet S. The orifice P5 of the plate 17 is open and
receives the pressurized liquid that arrives in the compartment 13
and is directed toward the chamber 5.
[0067] FIG. 4 represents an intermediate position of the slide
valve 16 in which the shutoff zones 32, 33 are in line with the
separation zones between the two orifices situated on either side
of the central orifice S of the plate 17. The orifices P5 and P6
communicate with the compartment 13 so that the pressure is
accepted both in the chamber 5 and in the chamber 6. The space 34
causes the two exhaust orifices E5, E6 to communicate with the
outlet orifice 5. In this intermediate position, the five orifices
are in complete communication and are all open at full section. The
flow of liquid passes through the chambers 5 and 6 and the
pressures balance out on either side of the membrane 7.
[0068] FIG. 5 represents the other extreme stable position of the
slide valve 16 in which the orifice P6 is open and receives the
pressurized fluid that is directed toward the chamber 6. The
orifices E6 and P5 are closed by the slide valve 16, while the
orifice E5 is placed in communication with the outlet S.
[0069] The shifted pitch on the one hand between the outlet orifice
S and the orifices E5, E6 and, on the other hand, between these
orifices E5, E6 and the orifices P5, P6 makes it possible, in the
extreme stable position of the slide valve 16, never to place the
inlet pressure in communication with the outlet chamber, while, in
the intermediate position of FIG. 4, all the orifices are in
communication without restriction in order to cause the pressure on
either side of the membrane 7 to fall.
[0070] The operation of the hydraulic motor and of the metering
device according to the invention is explained with reference to
FIGS. 1 and 6 to 13.
[0071] According to FIG. 6, the membrane 7 has reached the bottom
end of travel and the link rod 37 has switched over, under the
action of the spring 36, which has moved the distribution slide
valve 16 into the top stable position pressing against the stop 30.
In this position of the slide valve 16, the pressurized water
arriving through the inlet 14 is admitted via the open orifice P6
into the bottom chamber 6. The other orifice E6 communicating with
this chamber 6 is closed, while the orifice E5 is connected to the
outlet 18. The pressure that is applied in the chamber 6 on the
membrane 7 causes this membrane to deform toward the chamber 5 and
the pushbutton A to move upward according to FIG. 1. The liquid of
the chamber 5 is discharged through the orifice E5.
[0072] The end 36b of the spring 36 remains pressing against the
upper transverse wall of the housing 43 and holds the slide valve
16 in this position.
[0073] The raising of the pushbutton A causes the end 36a of the
spring 36 to rise. When the end 36a passes while rising, according
to FIG. 1, the horizontal plane passing through the shaft 38 of
articulation of the link rod 37, the latter switches over relative
to the pushbutton A such that the end 36a passes over the shaft 38
when looking at FIG. 1.
[0074] This step is represented schematically in FIG. 8, brought to
the horizontal. The end 36b of the spring moves into the housing 43
in order to press against the other transverse wall of the housing
43 and exert a pressure on the slide valve 16 in order to move it
toward the other stable position. Thanks to the geometry provided
for the link rod 37 and the arms 45, the end 45b of these arms
simultaneously presses against the stop 46 (FIG. 9). This
synchronous attack of the slide valve 16 assists the force of the
spring in order to overcome the resistance to sliding of the slide
valve 16.
[0075] FIGS. 10 and 11 represent the relative position of the link
rod 37 and of the slide valve 16 at the end of the assistance
provided by the arms 45. Since the slide valve 16 has begun its
travel, the forces to be developed for it to continue its travel
are less. The spring 36 can therefore finish moving the slide valve
toward the other stable position and the stop 46 moves away from
the end 45b as illustrated in FIGS. 12 and 13 which correspond to
the top end of travel of the pushbutton A, represented in FIG.
1.
[0076] In this other stable position, the pressure is admitted into
the chamber 5 while the chamber 6 is connected to the outlet. The
membrane 7 can deform downward and the pushbutton A can descend and
a new cycle occurs.
[0077] The alternating vertical movement of the membrane 7 and of
the pushbutton A allows the pumping and metering of the additive
thanks to the metering subassembly 21 whose pumping piston 24 is
driven by the membrane 7.
[0078] The slide valve 16 is held in place against the glass sheet
17 by the spring 36. In addition, the slide valve is pressed
against the glass sheet 17 by the pressure difference and the inlet
flow of the liquid when the liquid is flowing. The flatness and
surface finish of the slide valve 16 and of the glass sheet 17
ensure a good seal between the two elements.
[0079] The slide valve 16 sustains a force at right angles to the
glass sheet 17 equal to the bearing surface multiplied by the
pressure difference. The force to move the slide valve 16 is a
transverse force that is equal to the force at right angles to the
slide valve 16 multiplied by the friction coefficient between slide
valve 16 and glass sheet 17.
[0080] The movement of the membrane 7 is mechanically connected and
synchronized with the triggering of the switching. The movement of
the distribution slide valve on the glass sheet 17 is generated by
the rotary movement of the compression spring 36 which "balances"
the forces either to the first stable position or to the second
stable position, thereby generating the movement of the slide valve
16 by sliding.
[0081] The metering subassembly 21, connected to the membrane 7 via
the pushbutton 8, sucks then directly injects the additive product
at the outlet of the metering device.
[0082] The link rod 37, driven by the pushbutton A, compresses the
spring 36 and synchronizes the slide valve 16.
[0083] Specifically, in certain limiting conditions (pressure,
flow), the spring 36 may not be sufficient to cause sliding of the
slide valve 16 on which a pressure difference (pressure at the
inlet 14 of the metering device minus the pressure at the outlet
18) is exerted. The assistance provided by the link rod and the
arms 45 forms a synchronization which makes it possible to ensure
switching in these conditions: the slide valve is sufficiently
pushed by the arms 45 toward the intermediate position, illustrated
in FIGS. 10 and 11 and in FIG. 4, placing all the chambers of the
membrane in communication with the outlet and causing the pressure
difference to fall. The forces on the slide valve 16 fall and the
spring 36 causes the travel of the slide valve 16 to continue
toward the other stable position causing the switching. In the
event of a pressure difference and/or flow that is too high between
the inlet and the outlet of the metering device, or if there is a
breakage of the spring 36, the slide valve 16 is placed by the arms
45 in the intermediate position illustrated in FIG. 4 with the two
chambers 5, 6 placed in communication with the outlet, and
therefore the inlet 14 placed in communication with the outlet 18.
The main flow of liquid is not interrupted.
[0084] A membrane metering device according to the invention may
have a very low flow rate, for example 2 to 3 liters/hour. It may
operate under a low water pressure corresponding for example to 1
to 2 meters of head between the water source and the metering
device, that is approximately 0.1 to 0.2 bar.
[0085] Such a metering device makes it possible to move
particle-filled waters, particularly thanks to the operation with
membrane.
[0086] The flow rate range is very wide, able to go from 2-3 l/h to
2000 l/h for example. The operating pressure range is equally wide,
for example from 0.1 bar to 4 or 5 bar.
[0087] The metering of additive in the main liquid may be of the
order of 2% and even 5%.
[0088] As an indication, the cylinder capacity (flow per upward or
downward cycle) may be approximately 0.4 liter. The diameter of the
membrane may be of the order of 110 mm and the travel from 25 to 30
mm. The orifices in the plate 17 may have a section of
approximately 1.3 cm.sup.2.
[0089] The membrane metering device with switching by distribution
slide valve makes it possible to thoroughly separate the
distribution mechanism from the piston or membrane driving portion.
Accordingly, these elements can be removed independently of one
another.
* * * * *